Thulium (Tm)

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Thulium 69Tm168.93421


Discovered in 1879 by P.T. Cleve at Uppsala, Sweden.

[Called after Thule, an ancient name for Scandinavia]

French: thulium
German: Thulium
Italian: tulio
Spanish: tulio


Description: Thulium is a silvery metal, and rarest of the so-called rare earth group (more correctly termed the lanthanides). It tarnished in air and reacts with water. Thulium has few uses but some is employed as a radiation source in portable X-ray equipment.

  


Further Materials properties

 

Crystal structure:

(cell dimensions/pm), space group, 
h.c.p. (a=353.75, c=555.46) P63/mmc

X-ray diffractions mass absorption coefficients: CuKa 140 (µ/r) / cm2g-1
MoKa 80.8 (µ/r) / cm2g-1
Neutron scattering length: 0.707 b/10-12 cm
Thermal neutron capture cross-section: 100 sa / barns
Density: 9321 kg/m-3 [293 K]
Melting point: 1544.85°C / 1818°K
Boiling point: 1946.85°C / 2220°K
Molar volume: 18.12 cm3
Thermal conductivity: 16.8 [300 K] W m-1K-1
Coefficient of linear thermal expansion: 13.3 x 10-6 K-1
Electrical resistivity: 79.0 x 10-8 [295 K] Ωm
Mass magnetic susceptibility: +1.90 x 10-6(s) kg-1m3
Radi: Tm4+ 87Tm3+ 94; atomic 175; covalent 156
Electronegativity: 1.25 (Pauling); 1.11 (Allred); ≤3.4 eV (absolute)
Effective nuclear charge: 2.85 (Slater); 8.58 (Clementi); 11.80 (Froese-Fischer)
Number of Isotopes (incl. nuclear isomers): 28
Isotope mass range: 152 -> 176

 

 


Biological data

 

Biological role: None, but acts to stimulate metabolism.
Toxicity
Toxic intake: n.a.
Lethal intake: LD50 (chloride, oral, mouse) = 4290 mg Kg-1
Hazards: Thulium is mildly toxic by ingestion.
Level in humans
Organs: n.a., but low
Daily dietary intake: n.a.
Total mass of element in average
[70 kg] person:

n.a.


Geological data

 

 

Minerals:
MineralFormulaDensityHardnessCrystal apperance
Bastnäsite*  (Ce, La, etc.) CO3F  4.9  4 - 4.5  hex., vit/ greasy yellow
Monazite*  (Ce, La, Nd, Th, etc.)PO4  5.20  5 - 5.5  mon., waxy/ vit. yellow-brown

* although not a major constituent, thulium is present in extractable amounts.

Chief ores:  monazite, bastnäsite
World production:  c. 50 tonnes/year
Main mining areas:  USA, Brazil, India, Sri Lanka, Australia
Reserves:  c. 1 x 105 tonnes
Specimen:  available as chips, ingots or powder.

 

Abundances  
Sun: 1.8 (relative to H = 1 x 1012)
Earth's crust: 0.48 ppm
Seawater
Altantic surface: 1.3 x 10-7
Atlantic deep: 1.6 x 10-7
Pacific surface: 0.7 x 10-7
Pacific deep: 3.3 x 10-7
Residence time: n.a.
Classification: recycled 
Oxidation state: III

  Source: Emsley, J. (1998) The Elements (3rd Edition)

Other sizes and specifications on request


Overview of elements with access to our shop

1 18
H
2 13 14 15 16 17
He
Li Be B C
N
O
F
Ne
Na Mg 3 4 5 6 7 8 9 10 11 12 Al Si P S
Cl
Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se
Br
Kr
Rb Sr Y Zr Nb Mo
Tc
Ru Rh Pd Ag Cd In Sn Sb Te I
Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi
Po
At
Ra
Fr
Ra
Ac
Ce Pr Nd
Pm
Sm Eu Gd Tb Dy Ho Er Tm Yb Lu


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